How Heat Transfer Indirectly Affects Performance of Algae-Bacteria Raceways

Thermal response analysis and compilation of cardinal temperatures for 424 strains of microalgae, cyanobacteria, diatoms and other species

Microalgae and other phototrophic microorganisms can be cultivated to produce food and valuable bioproducts, also allowing to remove nutrients from wastewater and CO₂ from biogas or polluted gas streams. Among other environmental and physico-chemical parameters, microalgal productivity is strongly influenced by the cultivation temperature. In this review, cardinal temperatures identifying the thermal response, i.e., the optimal growth condition (T_OPT), and the lower and upper limits for microalgae cultivation (T_MIN and T_MAX), have been included in a structured and harmonized database. Literature data for 424 strains belonging to 148 genera of green algae, cyanobacteria, diatoms, and other phototrophs were tabulated and analysed, with a focus on the most relevant genera that are currently cultivated at the industrial scale in Europe. The dataset creation aimed at facilitating the comparison of different strain performances for different operational temperatures and assisting in the process of thermal and biological modelling, to reduce energy consumption and biomass production costs. A case study was presented, to illustrate the effect of temperature control on the energetic expenditure for cultivating different Chorella sp. strains under a greenhouse located in different European sites.